From the CAA Guidance document on Introductory Flights:
The aim of the introductory flights is to attract new trainees or new members. They are not designed, and should not be sold, to replace EASA Part FCL Exercise 3: Air Experience flight, in which a qualified instructor would typically give a demonstration of the controls and some flight training exercises with the participant handling the aircraft. Flight time as a passenger on an introductory flight will not count as training towards the grant of a pilot’s licence.
A marginal activity should be understood as representing a very minor part of the overall activity of the organisation. An organisation intending to offer such flights as regular business activity is not considered to meet the condition of a marginal activity.
Flights organised with the sole intent to generate income for the organisation are not considered to be a marginal activity.
" Flying Lesson Vouchers" would not count as an Introductory Flight.
I wonder if their insurers are aware of what is going on.